Various embodiments each include at least one of systems, devices, methods, and software for cross-channel security authentication, such as with regard to providing of payment card (e.g., credit and debit card) data for payment within a transaction. One such embodiment, in the form of a method includes receiving, by a payment account app on a mobile device, a payment authorization request and subsequently receiving approval or denial input within the payment account app following receipt of valid payment account authentication input. This method, following receipt of approval input, further includes generating authorized payment output to provide in response to the received payment authorization request.